import  sys
from PyQt5.QtWidgets import QApplication,QWidget
from PyQt5.QtGui import QIcon

class Example(QWidget):
    def __init__(self):
        super().__init__()

        self.initUI()

    def initUI(self):
        self.setGeometry(300,300,300,200)
        self.setWindowTitle('Icon')
        self.setWindowIcon(QIcon('Security.png'))
        self.show()

if __name__=='__main__':
    app = QApplication(sys.argv)
    ex=Example()
    sys.exit(app.exec_())